Yet he did not waver through unbelief regarding the promise of God, but was strengthened in his faith and gave glory to God, being fully persuaded that God had power to do what he had promised. This is why "it was credited to him as righteousness." The words "it was credited to him" were written not for him alone, but also for us, to whom God will credit righteousness--for us who believe in him who raised Jesus our Lord from the dead.
When you read these verses, it is just a great reminder that our righteousness, or our right-ness with God is made possible by our believing what God said and says.
The good news is that we are found in Him, not having a righteousness of our own by following the law, but one that is through faith in Jesus; the righteousness from God based on faith. Phil 3:9